The present invention relates to an compound, and more specifically to a compound used in an organic light-emitting diode.
Organic electroluminescent devices are popular in flat panel display due to their high illumination, light weight, self-illumination, low power consumption, simple fabrication, rapid response time, wide viewing angle, and no backlight requirement.
When an external electric field is applied to an organic electroluminescent device, electrons and holes are injected from cathode and anode, respectively, and then recombined to form excitons. Energy is further transported from excitons to luminescent molecules with continuous application of an electric field. Finally, luminescent molecules emit light converted from energy. A common organic electroluminescent device structure comprises an ITO anode, a hole transport layer, an emitting layer, a hole blocking layer, an electron transport layer, and a cathode. A complex organic electroluminescent device, however, may further comprise a hole injection layer disposed between an anode and a hole transport layer or an electron injection layer disposed between a cathode and an electron transport layer to improve injection efficiency of carriers, reducing driving voltage or increasing recombination thereof.
With development of synthesis techniques, various synthetic organic compounds for use in organic electroluminescent devices have been provided, with organic luminescent materials containing carbazole structure discussed herein. Currently, these luminescent materials containing carbazole structure have been used as hole transport material as disclosed in U.S. Pat. No. 6,660,410, J.P. PG-Pub. No. 2004071500, and G.P. Pat. No. 03/080761A1, as phosphorescent material as disclosed in J.P. Pat. No. 08-003547 and 09-310066, or as fluorescent material as disclosed in U.S. Pat. No. 6,649,772 and J.P. Pat. No. 07-150138.
Such related arts, however, do not disclose use of the organic luminescent materials containing carbazole structure in blue fluorescent devices. Additionally, related structures of substituted groups in 3,6-positions and nitrogen atom of carbazole are still simple, suitable for synthesis of more complicated structures. Thus, synthesis of novel blue fluorescent materials has a great potential in development of luminescent materials.